The transmission of e-mail messages over the Internet is a form of communication which is being used extensively and increasingly in both the workplace and the home. The capability of individuals to disseminate information over the Internet to large numbers of recipients with relatively minimal effort and cost makes e-mail a particularly attractive mechanism for the dissemination of advertising and promotional material and has spawned a substantial increase in the amount of unsolicited bulk e-mail messages being propagated. The content of these e-mail messages, commonly referred to as “spam”, varies widely but in the vast majority of cases, is of no interest to the recipient.
Senders of unsolicited bulk e-mail messages obtain databases of e-mail addresses by a variety of means. Commonly, senders obtain access to a directory such as a “whois” database which identifies one or more contact persons for registered domain names. The database provides the address, telephone number, and e-mail address of the contact person. Thus, a sender may query a “whois” database to obtain a database of e-mail addresses of all contact persons for the domain names in that particular “whois” database. Senders may also create a database of e-mail addresses by scanning web pages posted on the Internet or by querying other databases, both online and offline (i.e. in print), for users' e-mail addresses. Once a database of e-mail addresses has been compiled, it can be sold or otherwise disseminated to any interested person. Regardless of the method used, obtaining a database of e-mail addresses tends to be an extensive/expensive undertaking. As such, even if the sender appreciates that a certain proportion of the e-mail addresses in a database are no longer operative, the number of e-mail addresses in the database assumed to be operative warrants dispatching a bulk e-mail message to all addresses in the database.
The receipt by e-mail users of unsolicited bulk e-mail messages is problematic for a number of reasons. When an e-mail user receives an unsolicited bulk e-mail message, assuming that the user has no interest in the content of the message, the user reviews the message header and either deletes the message without opening it or opens the message, reviews it and then deletes it. Regardless how the e-mail user deals with the e-mail message, the user is required to spend time to review the message and ultimately delete it. If the e-mail user receives a large number of unsolicited bulk e-mail messages, the amount of time taken to deal with them becomes significant. In the workplace, the receipt of unsolicited bulk e-mails by employees negatively impacts on productivity. As well, the time taken by an e-mail user to receive and dispose of unsolicited bulk e-mail messages increases the online and network administration costs of the user or his or her employer. As most users pay for their access to the Internet, and as this access is typically charged based on the amount of time used, the cost of unsolicited bulk e-mails is borne by the receiver, not the sender.
Unsolicited bulk e-mail is also has a negative impact on the infrastructure of the Internet. Internet Service Providers (“ISP's”) must use their expensive bandwidth to transmit the bulk messages. In most cases, in addition to transmitting e-mail messages, the ISP also hosts the e-mail of the user until the user retrieves it. Carrying out these functions causes extreme loads on both the network connections and the servers involved. If a small ISP were to have 30,000 users, and each user were to receive an unsolicited bulk e-mail, each message being relatively small (200 words or 1,000 bytes), the ISP would need to import and store on its servers over 30 million bytes (30 Megabytes) of information for that one e-mail message alone. As a typical ISP can receive numerous such e-mail messages per day for its clients, the problem quickly amounts to gigabytes of wasted bandwidth and storage space. For large ISP's with 20 million users or more, one unsolicited bulk e-mail message can use over 20 gigabytes of storage and bandwidth.
To date, there have been few solutions proposed to eliminate or reduce the amount of unsolicited bulk e-mail received by e-mail users. The use of anonymous servers which do not reveal the identity of the e-mail user are known, however, these servers have traditionally simply provided anonymity with a static e-mail address. That is, a user is assigned an e-mail address that he or she can use for both ingoing and outgoing e-mail messages. This e-mail address never changes. Once it becomes known on the Internet, it can therefore be used to send people unsolicited bulk e-mail. Thus, although this system provides a level of anonymity, it does not effectively reduce the flow of unsolicited bulk e-mail.
As the volume of e-mail messages being sent over the Internet increases, e-mail users are an increasingly attractive target for unsolicited mail. The amount of unsolicited bulk e-mail is expected to increase and the problems associated with the receipt of bulk e-mail are therefore expected to worsen. Thus, there is a need for an effective and convenient means for reducing the amount of unsolicited bulk e-mail messages received by e-mail users.